In our U.S. Pat. No. 4,505,937 issued 19 March 1985 and based upon a French application filed 19 May 1981 and issued as French patent FR No. 2,506,127, we have described a process for the treatment of vegetables, especially potatoes, for marketing. The potatoes are subjected to selection, peeling and, if desired, cutting up into pieces and the resulting product is then treated in five successive stages in the following order:
(a) a light pasteurization effected at a temperature between substantially 75.degree. and 85.degree. C.;
(b) vacuum conditioning in plastic pouches, corresponding essentially to a vacuum packaging in the plastic pouches;
(c) a treatment resulting in the development of bacteria in the spore state and present in the potatoes in order to improve the vegetative condition thereof, i.e. incubation of bacteria, by subjecting the closed pouches containing the potato to a temperature of 25.degree. to 35.degree. C. in a treatment vessel;
(d) pasteurization at a temperature between 85.degree. and 90.degree. C.; and
(e) refrigeration or cooling.
Full details of the process can be found in the above-mentioned U.S. patent.
While this process has been found to be highly effective for potatoes and is also effective for other tubers, the number of vegetables with which it can be used is limited to those which can be subjected without danger to the pasteurization which constitutes the first phase (step (a)) of this process.
We have found that there are certain vegetables which do not tolerate well the initial pasteurization step. These include onions, leeks, garlic, shallots and like vegetables. Most fruits also do not tolerate the initial pasteurization well.